1. Field of the Invention
The present invention general relates to a board-to-board connector, and especially to a board-to-board connector having a receptacle and a plug which is capable of assuring a reliable interlock therebetween.
2. The Related Art
In the field of the electronics industry, in order to electrical connect two parallel printed circuit boards (PCBs), it is necessary to provide a surface mount miniature board-to-board connector which is composed of a receptacle with a plurality of first contacts and a plug with a plurality of second contacts. One end of the first and second contacts engages with each other, the other end of the first and second contacts connects to a printed circuit board respectively.
At present, the trend of consumer electronics such as a mobile telephone or a digital still camera constantly reduces its size. The board-to-board connector used in the miniaturization consumer electronic devices is correspondingly required tinier and tinier. Moreover, contacts of the connectors are arranged thicker and thicker. In this consequence, however, it becomes difficult to ensure a firmly engagement between the plug and the receptacle of the board-to-board connector.
It is desirable to retain the connector components in engagement with each other and fulfill their need. A locking mechanism has been developed for such connector. U.S. Pat. No. 5,876,217, issued on Mar. 2, 1999 discloses a traditional board-to-board connector described an interlock structure of a receptacle and a plug therebetween, as shown in FIG. 14. A plurality of receptacle contacts 50 are shaped to have a straight locking member 51 and a resilient contact member 52 paralleled  roughly with the locking member 51. A free end of the resilient contact member 52 extends inwardly to form a contact end 53 which engages with a resilient arm 61 of a plurality of plug contacts 60.
In the above-mentioned board-to-board connector, an interlock between the receptacle and the plug is achieved through the locking member 51 engaging with a locking recess 71 formed on a plug body 70. When the plug inserts into the receptacle, the plug body 70 slides into a channel formed between the resilient contact member 52 and the locking member 51 along a substantial vertical direction. In the process of the plug body 70 pressed contacting the locking member 51, a moment arm of the pressed contact torque is so short because of a straight design of the locking member 51. Therefore, it is necessary to act a large force on the locking member 51 to accomplish the foregoing insertion process. As a result, the locking member 51 may be broken or yielded due to a large stress resulted from the large force, further it can't realize a stable interlock between the receptacle and the plug.